Chronic infection with hepatitis C virus (HCV) is a major cause of chronic liver disease, with long term consequences including cirrhosis and hepatocellular carcinoma. Currently, the only approved treatment for HCV is Interferon Alfa (INF-alfa) alone or in combination with ribavirin. RhIL-12 has been shown to have activity against HCV infection in phase I trials. This study is designed to further assess the antiviral activity and safety of rhIL-12.